Degradation pathways and impurity profiling of the anticancer drug apalutamide by HPLC and LC-MS/MS and separation of impurities using Design of Experiments.

Apalutamide, an androgen receptor inhibitor, is used to treat prostate cancer. A stability-indicating high-performance liquid chromatography method was developed for the estimation of assay and organic impurities of apalutamide in drug substance and in tablet dosages using Design of Experiments. The chromatographic separation was achieved within 30 min using Atlantis dC18 , 100 × 4.6 mm, 3.0 µm and the binary gradient program (10 mm KH2 PO4 , pH 3.5; acetonitrile). The detection wavelength, flow rate, column temperature and injection volume used were 270 nm, 1.0 ml/min, 45°C and 10 µl, respectively. The interaction of independent variables (pH, column temperature and flow rate) and their influences on HPLC parameters were studied using a central composite design, and then the peak separation and elution behaviors between apalutamide and its seven impurities were determined. The method validation was performed for linearity, detection limit, quantitation limit, accuracy, precision and robustness as per the International Conference on Harmonization. A high-quality recovery with good precision (91.7-106.0%) and correlations (r2 > 0.997) within a linear range of 0.12-2.24 µg/ml (0.05-0.3%, w/w) were achieved consistently for assay and organic impurities of apalutamide. The stability-indicating characteristics of the proposed method were assessed through forced degradation and mass balance studies. An effort was made to figure out the chemical structures of newly formed degradation products (DP1-DP5) using LC-MS/MS.

Effect of hydro-geochemical processes and saltwater intrusion on groundwater quality and irrigational suitability assessed by geo-statistical techniques in coastal region of eastern Andhra Pradesh, India.

Sustainable management of groundwater needs comprehensive study on water quality in present scenario. Hence, an understanding on the hydro geochemistry, saltwater intrusion, spatiotemporal-seasonal variations and irrigational suitability of groundwater becomes a must, especially in coastal regions. Our study area is one such place where all the parameters play a major role against sustainable management. The study pointed out that majority of the samples is brackish with two notable geochemical facies for pre monsoon and post monsoon. Factor and cluster analyses revealed that EC, TDS, Na+, Cl-, Mg2+ and Ca2+ are the major contributors. Gibb's diagram supported the dominance of rock weathering and evaporation in controlling the groundwater chemistry. Sea water intrusion was mapped using HFE diagrams and the Irrigational suitability is studied using USSL, SAR, %Na, etc. The data and results from this study might provide crucial information to water management authorities in dealing groundwater scarcity and pollution problems.

Development and validation of liquid chromatography-tandem mass spectrometry method for the estimation of a potential genotoxic impurity 2-(2-chloroethoxy)ethanol in hydroxyzine.

2-(2-Chloroethoxy)ethanol (CEE) belongs to the so-called cohort of concerns which were classified as highly potent mutagenic carcinogens by the World Health Organization. It is widely used in the synthesis of the essential anti-histamine drug hydroxyzine. In addition, it is used as a primary solvent in dyes, nitrocellulose, paints, inks and resins. Owing to its potential genotoxicity, an efficient liquid chromatography-tandem mass spectrometry method was developed for the quantitative estimation of CEE traces in an active pharmaceutical ingredients and in tablet dosage forms of hydroxyzine-free base. The chromatographic separation was achieved on a C18 column using a gradient elution mode with a binary solvent system (ammonium formate and methanol). Mass detection was performed for CEE using a positive mode with selected ion monitoring technique at m/z value of [M + NH4 ]+ . The developed method was validated as per the International Conference on Harmonizaiton guidelines. The quantitation limit, linearity and recoveries were found to be 0.56 ppm, 0.56-7.49 ppm (r2 > 0.9985) and 93.6-99.3%, respectively. The proposed method was highly compatible and was used effectively to estimate CEE traces in different stages of drug synthesis and in tablet dosage forms of hydroxyzine for routine and stability testing.

Impurity profiling and stability-indicating method development and validation for the estimation of assay and degradation impurities of midostaurin in softgel capsules using HPLC and LC-MS.

Midostaurin (MDS) is used for the treatment of acute myeloid leukemia, myelodysplastic syndrome, and advanced systemic mastocytosis. MDS softgel capsule samples were subjected to stress testing per International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use guidelines for impurity profiling study. MDS underwent extensive degradation under stress testing (acid, alkaline, oxidative, photolytic, thermolytic, and hydrolysis conditions) and formed four degradation products (DPs). MDS and its DPs were separated well from one another with good resolution using reserved-phase HPLC using an Inertsil ODS-3V column (250 × 4.6 mm, 5 µm) and a mobile phase of ammonium formate (40 mM) and acetonitrile. The stability-indicating characteristic of the newly developed method was proven for the estimation of MDS assay, and its organic impurities were free from interference. The validated method exhibited excellent linearity, accuracy, precision, specificity, detection limit, and quantitation limit within 25 min run time. Stress testing, robustness, and solution stability were performed to ensure the continuous performance of the developed method. The peak fractions of DPs formed under stress testing were isolated and characterized using LC-MS, 1 H and 13 C NMR, IR, and UV-Vis. The structure of the major DPs was predicted as DP1 based on the spectral data. The proposed method is effectively used for MDS in bulk drug and finished formulations in the pharmaceutical industry.

[Impurity profile of macitentan in tablet dosage form using a stability-indicating high performance liquid chromatography method and forced degradation study].

Macitentan (MAC) is a pulmonary arterial hypertension (PAH) drug marketed as a tablet and often has stability issues in the final dosage form. Quantitative determination of MAC and its associated impurities in tablet dosage form has not been previously reported. This study quantified impurities present in Macitentan tablets using a binary solvent-based gradient elution method using reversed phase-high performance liquid chromatography. The developed method was validated per International Conference on Harmonization (ICH) guidelines and the drug product was subjected to forced degradation studies to evaluate stability. The developed method efficiently separated the drug and impurities (48 min) without interference from solvents, excipients, or other impurities. The developed method met all guidelines in all characteristics with recoveries ranging from 85%-115%, linearity with r2 ≥ 0.9966, and substantial robustness. The stability-indicating nature of the method was evaluated using stressed conditions (hydrolysis:1 N HCl at 80℃/15 min; 1 N NaOH at 25℃/45 min; humidity stress (90% relative humidity) at 25℃ for 24 h, oxidation:at 6% (v/v) H2O2, 80℃/15 min, thermolysis:at 105℃/16 h and photolysis:UV light at 200 Wh/m2; Fluorescent light at 1.2 million luxh). Forced degradation experiments showed that the developed method was effective for impurity profiling. All stressed samples were assayed and mass balance was>96%. Forced degradation results indicated that MAC tablets were sensitive to hydrolysis (acid and alkali) and thermal conditions. The developed method is suitable for both assay and impurity determination, which is applicable to the pharmaceutical industry.